If you have ever delivered a formatted SRT file to a client and received a rejection for a problem that had nothing to do with the text, you have already learned this the hard way. The English was correct. The style guide rules were applied. The file looked clean in the editor. And then it broke in the player — wrong line breaks, misaligned timecodes, cue boundaries that no longer matched the audio. The formatting pass that fixed the text broke the structure. Because the tool doing the formatting did not know the structure existed. This is the most common and least-discussed failure mode in caption file formatting for clients. And it happens because most transcription and editing tools treat SRT and VTT files as plain text with timestamps attached. They are not. They are structured documents where the text and the structure are interdependent. What makes caption files structurally different A plain transcript is a linear text document. Formatting rules apply to the text.…